Questions about R

You can get details at http://www.r-project.org/

But to answer your question: Yes it is free

But there is also a paid version. Send me $1000 and I will send you R
on a USB stick, complete with all the source code.

 Seriously, other companies do supply support and extensions for R at
a cost, and although I can legally sell you a copy of R for $1000
nobody bothers charging for R because the license can't stop you
giving your copy away.

 As for your security/data safety question, well your operating system
is probably the weaker link in that chain. However if you are running
R in a client-server fashion then you should make sure the data is
encrypted - and then the weakest link is possession of the private
half of the encryption key, which is your responsibility.

Barry